The composition and diversity of biomass for producing cellulosic ethanol requires multiple enzyme systems, in very high concentrations, to release constituent sugars from which cellulosic ethanol is made. All currently available enzymes for cellulosic ethanol are produced in expensive fermentation systems and are purified in a process very similar to biopharmaceuticals like insulin. Therefore, reagent grade enzymes for ethanol production are extremely expensive. For example, B-glucosidase, pectolyase and cellulase are currently sold by Novozyme through the Sigma catalog for $124,000, $412,000 and $40,490 per kg, respectively. These enzymes are sold as formulations to bio-refineries without disclosing the actual enzyme components. Therefore, the actual cost for each enzyme, sold in bulk quantities, is not publicly available. Most industrial estimates for enzymes to produce cellulosic ethanol are in the $2 to $3 per gallon range, making large scale use cost prohibitive. Current capacity of fermentation systems will also be a major limitation. With increase in demand for enzymes and limited production capacity, the enzyme cost is likely to increase further.
A major limitation for the conversion of this biomass to ethanol is the high cost and large quantities of enzymes required for hydrolysis. B-glucosidase, pectolyase and cellulase are currently sold by Novozyme or other industries through the Sigma catalog for $124,000, $412,000 and $40,490 per kg, respectively. Therefore, the US DOE has long identified the cost of enzymes and their high loading levels required for most lingo-cellulosic feedstocks as one of the major barriers to cellulosic ethanol production. Currently, all commercially-available enzymes are produced through a fermentation process. Unfortunately, the building and maintenance of the fermentation production process is very expensive, costing $500M-$900M in upfront investment. No viable alternative to fermentation technology has yet emerged for mass-producing critical, yet prohibitively expensive industrial enzymes. This void in the marketplace for an alternative process is addressed directly by this proposal.